The present invention relates generally to the field of lighting for signs and displays and in particular to a new and useful gas discharge tube color display generator having a digital and/or analog programmable control circuit used to regulate power to multiple gas discharge lamps. The system of the invention can be used to create varying gas lighting displays which are quickly and easily changed, stored, recalled and repeated.
Neon signs are widely used to advertise businesses with eye-catching colors and designs. This is especially true in cities like New York City and Las Vegas, Nevada.
As used herein, the term "neon sign" refers to several types of excited gas discharge tube displays. While neon is a common inert gas found in the discharge tubes of lighting displays, other inert gases as well as mercury vapor are also used in lighting displays. As used herein, "neon" and "gas discharge tube" are intended to encompass all of the gases and vapors known for use in lighting discharge tubes and tubes using any known gas or vapor, respectively, unless otherwise specified and is not intended to limit the invention to discharge tubes using only neon gas.
Neon lights can be made to produce different colors by changing the physical construction of the discharge tube. To cause a discharge tube to produce a particular color one or more of the following are changed: 1) the gas in the tube; 2) a phosphor coating on the tube; or 3) a filter on the tube. These three factors can be used alone or in combination to produce different colors.
A common type of display sign typically has a discharge tube mounted behind a translucent sheet of material which contains the design or color being illuminated. This type of display is generally static, in that the design of the sign cannot change. The discharge tubes used in this type of sign generally emit white light behind the sheet of material. Neon, fluorescent and incandescent lighting can all be used to illuminate this type of sign.
Another type of neon sign uses discharge tubes to provide an outline of a design. The discharge tubes usually contain a single gas, such as neon, argon, xenon, etc., which emits light in the visible spectrum when excited by electrical energy. Methods used to generate the different colors in the light spectrum in these types of signs are to use different gases in the discharge tubes and to use different phosphorescent coatings on the tubes. The color of the tube is not changeable once the tube has been filled with a single gas or coated with a particular phosphorescent coating. In some cases these signs exhibit movement by switching sections of the discharge tubes on and off, such as between two different arm positions on a display pointing to a business.
In each of these two cases, however, the color of the sign cannot be changed without changing the sign or the discharge tubes.
Changeable lighting displays, such as found on sports stadium scoreboards, use individual single color incandescent lightbulbs which are either lit or darkened to produce a picture when viewed from a distance. Some incandescent bulb displays show messages which are made to appear to move across the display area by rapidly switching the bulbs in sequence.
A luminous tube using noble gases to produce light of different hues is taught by U.S. Pat. No. 4,598,229. The tube has an outer tube and three or more inner tubes mounted inside the outer tube. The three inner tubes each have one cathode electrode, and a common anode electrode is provided in the outer tube. The same inert gas fills each of the three tubes. The inner tubes can each be coated with a different phosphorescent coating to provide a different primary light color when they are illuminated, that is, red, blue and green. From a distance, the tube will appear to be a single color which is the combination of the three colors of the inner tube. The color of light emitted by the tube can be changed by varying the current density to each cathode.
However, a lighting tube of this type is impractical if not impossible to effectively use in a lighting display designed for depicting free flowing shapes or driving tubes of extended length.
None of the known neon lighting systems has a control system which permits rapid changing and storing and recalling of the display and/or complex sequencing using different color combinations created using the control system.